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Selective inhibition of MAO-A in serotonergic synaptosomes by two amphetamine metabolites, p-hydroxyamphetamine and p-hydroxynorephedrine. Neurochem Int 2012; 17:587-92. [PMID: 20504661 DOI: 10.1016/0197-0186(90)90046-v] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/1989] [Accepted: 04/03/1990] [Indexed: 11/20/2022]
Abstract
The present study was carried out mainly to clarify whether the two amphetamine metabolites, p-hydroxyamphetamine (P-OHA) and p-hydroxynorephedrine (p-OHN) are taken up by mouse brain 5-hydroxytryptamine (5-HT) nerve terminals to inhibit type A monoamine oxidase (MAO-A) and then potentiate the abnormal behavior, head-twitch. Of the two metabolites, only intracerebroventricular p-OHA, at 80 ?g/mouse, sufficient to cause a head-twitch response (HTR), appreciably inhibited MAO-A activity without affecting MAO-B activity in homogenates of the mouse striatum, hypothalamus and the rest of the forebrain; and p-OHN did not inhibit either type of MAO at the dose tested. Estimation of intra- and extrasynaptosomal MAO-A activity showed that both metabolites significantly inhibited only the intrasynaptosomal deamination of 5-HT by MAO-A with p-OHA being more potent. Taken together with our previous findings, these present results clearly indicate that p-OHA may accumulate in the 5-HT nerve terminals through the uptake system, and concomitantly inhibit MAO-A activity. These actions of p-OHA may increase intraneuronal 5-HT levels and then potentiate 5-HT release to cause interaction with the post-synaptic 5-HT receptors.
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2
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Ito T, Suzuki K, Uchida K, Nakayama H. Different susceptibility to 1-methyl-4-phenylpyridium (MPP(+))-induced nigro-striatal dopaminergic cell loss between C57BL/6 and BALB/c mice is not related to the difference of monoamine oxidase-B (MAO-B). ACTA ACUST UNITED AC 2011; 65:153-8. [PMID: 21855308 DOI: 10.1016/j.etp.2011.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 06/01/2011] [Accepted: 07/22/2011] [Indexed: 10/17/2022]
Abstract
Subcutaneous and intraperitoneal administrations of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induce selective dopaminergic (DA-ergic) neuronal death in many animal species. After passing through the blood-brain barrier (BBB), MPTP is converted to 1-methy-4-phenylpiridinium (MPP(+)) by astrocytic monoamine oxidase-B (MAO-B). MPP(+) then induces the dopaminergic neuronal death. In mice, marked strain differences in the susceptibility to MPTP-injection have been reported. To clarify which factor(s) cause the strain differences, MPTP or MPP(+) was intracerebroventricularly (icv) injected into adult C57BL/6 (highly susceptible to MPTP) and BALB/c (resistant to MPTP) mice. The brain tissues including the striatum and substantia nigra pars compacta (SNpc) were examined immunohistochemically using an antibody to tyrosine hydrocyrase (TH). MPP(+)-injected C57BL/6 mice showed a significant decrease in TH-immunopositive areas in the striatum at Day 3 post injection (p<0.01), and TH-positive cells in the SNpc at Days 1 and 3 (p<0.01), respectively, compared to saline-injected control mice. In addition, MPP(+)-injected BALB/c mice showed a significant decrease in TH-positive areas in the striatum at Days 1 and 3, and SNpc TH-positive cells in the SNpc at Day 3, respectively (p<0.05). However, the decrease rates in the BALB/c mice were lower than that in C57BL/6 mice. MPTP-injected C57BL/6 mice, however, showed no lesions in the striatum and SNpc at Days 1 and 7 after icv injection. All the present findings indicate that factors other than MAO-B can influence the strain susceptibility between C57BL/6 and BALB/c mice after the conversion from MPTP to MPP(+).
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Affiliation(s)
- Tsuyoshi Ito
- Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo 113-8657, Japan
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3
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Allen EMG, Anderson DGR, Florang VR, Khanna M, Hurley TD, Doorn JA. Relative inhibitory potency of molinate and metabolites with aldehyde dehydrogenase 2: implications for the mechanism of enzyme inhibition. Chem Res Toxicol 2010; 23:1843-50. [PMID: 20954713 DOI: 10.1021/tx100317q] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molinate is a thiocarbamate herbicide used as a pre-emergent in rice patty fields. It has two predominant sulfoxidation metabolites, molinate sulfoxide and molinate sulfone. Previous work demonstrated an in vivo decrease in liver aldehyde dehydrogenase (ALDH) activity in rats treated with molinate and motor function deficits in dogs dosed chronically with this compound. ALDH is an enzyme important in the catabolism of many neurotransmitters, such as dopamine. Inhibition of this enzyme may lead to the accumulation of endogenous neurotoxic metabolites such as 3,4-dihydroxyphenylacetaldehyde, a dopamine metabolite, which may account for the observed neurotoxicity. In this study, the relative reactivity of molinate and both of its sulfoxidation metabolites toward ALDH was investigated, as well as the mechanism of inhibition. The ALDH activity was monitored in two different model systems, human recombinant ALDH (hALDH2) and mouse striatal synaptosomes. Molinate sulfone was found to be the most potent ALDH inhibitor, as compared to molinate and molinate sulfoxide. The reactivity of these three compounds was also assessed, using N-acetyl Cys, model peptides, and hALDH2. It was determined that molinate sulfone is capable of covalently modifying Cys residues, including catalytic Cys302 of ALDH, accounting for the observed enzyme inhibition.
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Affiliation(s)
- Erin M G Allen
- Division of Medicinal and Natural Products Chemistry, College of Pharmacy, The University of Iowa, Iowa City, Iowa 52242, USA
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Cook R, Lu L, Gu J, Williams RW, Smeyne RJ. Identification of a single QTL, Mptp1, for susceptibility to MPTP-induced substantia nigra pars compacta neuron loss in mice. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2003; 110:279-88. [PMID: 12591164 DOI: 10.1016/s0169-328x(02)00659-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The loss of substantia nigra pars compacta (SNpc) neurons seen in idiopathic Parkinson's disease is hypothesized to result from a genetic susceptibility to an unknown environmental toxin. MPTP has been used as a prototypical toxin, since exposure to this drug results in variable SNpc cell death in several vertebrate species, including man and mouse. Previously, we have shown that C57BL/6J mice are sensitive to this compound, while Swiss-Webster mice are resistant. In this study, we intercrossed these mouse strains to map quantitative trait loci (QTL) for MPTP sensitivity. Using genome wide PCR analysis, we found that a single major QTLs, Mptp1, located near the distal end of chromosome 1 between D1Mit113 and D1Mit293, accounts for the majority of the strain sensitivity to MPTP.
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Affiliation(s)
- Ruby Cook
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 332 North Lauderdale, Memphis, TN 38105-2794, USA
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6
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Klein BG, Kirby ML, Freeborn ER, Bloomquist JR. Pharmacological properties of the MPTP analog trans-1-methyl-4-[4-dimethylaminophenylethenyl]-1,2,3,6-tetrahydropyridine and its pyridinium metabolite in mouse brain synaptosomes: a potential visual marker for substrates of MPTP-induced neurotoxicity. Prog Neuropsychopharmacol Biol Psychiatry 2001; 25:591-608. [PMID: 11370999 DOI: 10.1016/s0278-5846(00)00177-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
1. The tetrahydropyridine trans-1-methyl-4-[4-dimethylaminophenylethenyl]-1,2,3,6-tetrahydropyridine (t-THP), like MPTP, can undergo monoamine oxidase (MAO)-mediated conversion to a dihydropyridinium intermediate and subsequent metabolism to a pyridinium species. t-THP is also a better substrate for MAO B than MAO A. In contrast to the metabolism of MPTP, the pyridinium ion derived from t-THP is highly fluorescent. This endows t-THP with potential as an in vivo visual probe for localizing the substrates of MPTP-like neurotoxicity. As a prelude to in vivo labeling studies, we examined the metabolism and uptake kinetics of t-THP and its metabolites in mouse striatal and cortical synaptosomes. 2. T-THP was found to induce a concentration-dependent and saturable fluorescence within striatal and cortical synaptosomes that was also MAO-dependent. Like MPP+, the fluorescent pyridinium ion t-P+, derived from t-THP, inhibited the uptake and facilitated the release of monoamines from synaptosomes in a concentration-dependent fashion. The ion did not rely on sodium-dependent membrane transporters for its concentration-dependent uptake into synaptosomes, although it may have an irreversible affinity for the dopamine transporter. 3. These data suggest that t-THP could be appropriate for use as a visual marker for microenvironments where MPTP-like compounds are taken up and converted to potentially neurotoxic pyridinium species. Such a marker could be employed to address some of the issues regarding the selectivity of MPTP-induced neurotoxicity.
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MESH Headings
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/analogs & derivatives
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/chemistry
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/pharmacokinetics
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/pharmacology
- Animals
- Cerebral Cortex/metabolism
- Corpus Striatum/metabolism
- Dopamine/metabolism
- Dose-Response Relationship, Drug
- Male
- Mice
- Mice, Inbred ICR
- Monoamine Oxidase Inhibitors/pharmacokinetics
- Neurotoxins/metabolism
- Neurotoxins/pharmacology
- Pargyline/pharmacokinetics
- Serotonin/metabolism
- Synaptosomes/metabolism
- gamma-Aminobutyric Acid/metabolism
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Affiliation(s)
- B G Klein
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, 24061-0442, USA.
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Hamre K, Tharp R, Poon K, Xiong X, Smeyne RJ. Differential strain susceptibility following 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration acts in an autosomal dominant fashion: quantitative analysis in seven strains of Mus musculus. Brain Res 1999; 828:91-103. [PMID: 10320728 DOI: 10.1016/s0006-8993(99)01273-1] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been used as a potent neurotoxin to approximate, in animals, the pathology that is observed in human Parkinson's disease. In this study, we examine the toxicity of MPTP in seven strains of mice, spanning a genetic continuum of Mus musculus as a prelude to uncovering complex traits associated with MPTP toxicity. Seven days following injection of 80 mg/kg MPTP (4x20 mg/kg every 2 h), we find that the individual mouse strains exhibit dramatic differences in SNpc neuron survival, ranging from 63% cell loss in C57BL/6J mice to 14% cell loss in Swiss-Webster (SW) mice. In order to determine if the susceptibility trait was dominant, additive or recessive, we crossed C57Bl/6J mice with either SWR/J or AKR/J mice and examined the effect of MPTP on F1 C57BL/6JxSWR/J or F1 C57BL/6JxAKR/J animals. We find that all of the F1 animals were phenotypically identical to the C57BL/6J animals. In addition, no gender differences were noted in any of the MPTP-treated inbred mice or in the F1 animals. These results suggest that susceptibility to cell loss following MPTP is autosomal dominant and this polymorphism is carried on the C57BL/6J allele.
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Affiliation(s)
- K Hamre
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 332 North Lauderdale, Memphis, TN 38105, USA
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Sundström E, Samuelsson EB. Comparison of key steps in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxicity in rodents. PHARMACOLOGY & TOXICOLOGY 1997; 81:226-31. [PMID: 9396088 DOI: 10.1111/j.1600-0773.1997.tb00051.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Three steps in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxicity were compared with the neurodegenerative effects of the toxin in mice and rats. Firstly, we compared the neurotoxicity of MPTP, mediated by monoamine oxidase (MAO)-B, to that of 1-methyl-4-(2'-methylphenyl)-1,2,3,6-tetrahydropyridine (2'-CH3-MPTP), an analogue oxidized by MAO-A and MAO-B. Both toxins caused degeneration of dopamine terminals in mice but not in rats. In NMRI mice noradrenaline terminals were also affected by both toxins. Pretreatment with deprenyl to prevent MAO-B-mediated oxidation in the capillary endothelium enhanced dopamine toxicity to 2'-CH3-MPTP in nucleus accumbens but no potentiation was seen in striatum and the olfactory tubercle. Secondly, synaptosomal uptake of the 1-methyl-4-phenylpyridinium ion (MPP+) was studied. Uptake in rats was not significantly different from that in the two mice strains. Thirdly, no significant differences were found in MPP(+)-induced lactate production in striatal slices or synaptosomes. We conclude that the lack of effect of MPTP in rats is not due to mechanisms specific for MPTP but probably to the ability of rat catecholamine neurons to cope with, and survive, impaired energy metabolism.
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MESH Headings
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/analogs & derivatives
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/metabolism
- 1-Methyl-4-phenylpyridinium/metabolism
- Animals
- Brain/drug effects
- Brain/metabolism
- Dopamine/metabolism
- Lactic Acid/metabolism
- MPTP Poisoning
- Male
- Mice
- Mice, Inbred C57BL
- Norepinephrine/metabolism
- Parkinson Disease, Secondary/chemically induced
- Parkinson Disease, Secondary/metabolism
- Rats
- Rats, Sprague-Dawley
- Synaptosomes/drug effects
- Synaptosomes/metabolism
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Affiliation(s)
- E Sundström
- Division of Geriatric Medicine, Karolinska Institutet, Huddinge University Hospital, Sweden
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Liu Y, Edwards RH. The role of vesicular transport proteins in synaptic transmission and neural degeneration. Annu Rev Neurosci 1997; 20:125-56. [PMID: 9056710 DOI: 10.1146/annurev.neuro.20.1.125] [Citation(s) in RCA: 215] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Classical neurotransmitters are synthesized in the cytoplasm, so they require transport into secretory vesicles for regulated exocytotic release. Previous work has identified distinct vesicular transport activities for the different classical transmitters, and all depend on the H+-electrochemical gradient across the vesicle membrane but differ in the extent to which they rely on the chemical and electrical components of this gradient. Drugs that interfere with vesicular amine transport have implicated this activity in psychiatric disease. Selection for a cDNA encoding vesicular amine transport in the neurotoxin MPP+ also implicates the activity in Parkinson's disease. Molecular cloning of vesicular monoamine transporters shows sequence similarity to bacterial antibiotic resistance proteins, supporting a role for transport in detoxification and defining a novel mammalian gene family that now also includes a transporter for acetylcholine. Current work focuses on the mechanism of transport and the role that regulation of activity and its subcellular localization have in transmitter release, behavior, and neural degeneration.
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Affiliation(s)
- Y Liu
- Department of Neurology, University of California San Francisco 94143-0435, USA
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10
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Andersen JK, Frim DM, Isacson O, Beal MF, Breakefield XO. Elevation of neuronal MAO-B activity in a transgenic mouse model does not increase sensitivity to the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Brain Res 1994; 656:108-14. [PMID: 7804823 DOI: 10.1016/0006-8993(94)91371-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
To examine whether expressing high levels of monoamine oxidase (MAO-B) activity abberently in neurons results in increased sensitivity of dopaminergic neurons to the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), 8-week-old transgenic mice expressing high neuronal levels of MAO-B were compared with age-matched nontransgenic littermates following i.p. injections of 30 mg/kg body weight of the protoxin. Levels of striatal dopamine (DA) and its metabolite 3,4-dihydroxyphenylacetic acid (DOPAC), as well as tyrosine hydroxylase (TH)-immunopositive cell numbers in the substantia nigra (SN) were compared 1 week later between transgenics and controls. No difference was found in any of these parameters, indicating that high neuronal MAO-B levels does not cause increased sensitivity to MPTP, and therefore neither conversion of MPTP to its active form, 1-methyl-4-phenyl pyridium (MPP+) by MAO-B nor MPP+ uptake by the dopaminergic transporter are likely to be the rate-limiting step in the toxicity of this compound.
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Affiliation(s)
- J K Andersen
- Neurology Service, Massachusetts Hospital, Charlestown
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11
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A Study of the Biological Pharmacology of IFO, a New Selective and Reversible Monoamine Oxidase-B Inhibitor. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/s0021-5198(19)35793-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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12
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Nakamura S, Akiguchi I, Kimura J. The histochemical demonstration of MPTP oxidation in the postmortem human striatum. Neurosci Lett 1993; 154:61-4. [PMID: 8103202 DOI: 10.1016/0304-3940(93)90171-g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Monoamine oxidase (MAO) histochemistry has been performed in postmortem human striatal tissues using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) as substrate. The reaction products of MPTP oxidation in the human putamen and caudate nucleus were observed in glial cells. Although glial staining was found diffusely in the human striatum, prominently intense staining was observed in glial cells surrounding vessels. Double staining for MAO and glial fibrillary acidic protein showed that glial cells containing MAO activity were astrocytes. The inhibition experiments using clorgyline and 1-deprenyl as MAO inhibitors indicate that MAO associated with the present MPTP oxidation was of the B type. The present observations suggest that astrocytes, especially around vessels, may be involved in MPTP oxidation in the human striatum after systemic administration of MPTP.
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Affiliation(s)
- S Nakamura
- Department of Neurology, Faculty of Medicine, Kyoto University, Japan
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13
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Wahlström G, Magnusson O, Nordberg A, Stenström A, Tiger G. Temporal studies of the inhibition of voluntary ethanol intake in the rat induced by intermittent ethanol treatment and some long term neurochemical consequences. Drug Alcohol Depend 1991; 28:129-44. [PMID: 1718674 DOI: 10.1016/0376-8716(91)90069-b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Male rats were injected with ethanol (groups 3 and 5; 2.0 g/kg i.p.) or saline (groups 2 and 4) once a week for 52 weeks. The rats had access to ethanol as a voluntary choice for 24 h either once 6 days after the injection (groups 2 and 3) or twice 3 and 6 days after the injection (groups 4 and 5). At the beginning of the treatment ethanol injections inhibited voluntary ethanol intake if tested 6 days later (groups 3 and 5), but a tolerance developed to this inhibition. During tolerance development the rats in group 5 also drank less ethanol on day 3 than on day 6. No corresponding behaviour was seen in group 4. Thus part of the tolerance was a gradual reduction of the duration of inhibition. During the evaluation period (25 weeks) after the treatment, ethanol exposure (20 weeks) consisted of a continuous choice between ethanol and water. Of different ethanol concentrations both ethanol-injected groups (3 and 5) took the same voluntary dose of ethanol independent of the offered concentration. After 5 weeks without ethanol all rats were killed and a number of neurochemical variables were determined. Compared with almost unexposed rats (group 1) changes were seen in inositol phospholipid breakdown, muscarinic binding sites in hippocampus, noradrenaline concentrations in frontal cortex, hippocampus and hypothalamus, dopamine concentration in frontal cortex and 5-hydroxytryptamine concentration in hypothalamus. In most cases the largest changes were seen in group 5. None of the variables had a constant relation to ethanol intake in the total population. However, significant correlations were found in some of the groups.
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Affiliation(s)
- G Wahlström
- Department of Pharmacology, University of Umeå, Sweden
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14
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Arai Y, Kim SK, Kinemuchi H, Tadano T, Oyama K, Satoh N, Kisara K. Inhibition of brain MAO-A and animal behaviour induced by p-hydroxyamphetamine. Brain Res Bull 1991; 27:81-4. [PMID: 1933439 DOI: 10.1016/0361-9230(91)90284-q] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Intra- and extra-synaptosomal activity of monoamine oxidase-A (MAO-A) and -B (MAO-B), dopamine (DA) and its main metabolites were examined to clarify the mechanism of action(s) of p-hydroxyamphetamine (p-OHA) in animal behaviour mediated by central dopaminergic systems. Intrasynaptosomal DA was oxidized by MAO-A and MAO-B and this oxidation is inhibited by p-OHA. The inhibition is due to two effects: 1) uptake of DA is inhibited by p-OHA, and 2) p-OHA also inhibits intrasynaptosomal oxidation of DA by MAO-A and MAO-B. The inhibition of oxidation by MAO-A is predominant. Administration (ICV) of 80 and 160 micrograms p-OHA to mice, doses that cause various behavioural, significantly reduced striatal DA and 3,4-dihydroxyphenylacetic acid (DOPAC) levels, but greatly increased 3-methoxytyramine, without significantly changing homovanillic acid (HVA). The release of DA and blockade of DA uptake into dopaminergic neurons by p-OHA, together with preferential inhibition of the DA metabolizing enzyme, MAO-A, may contribute to p-OHA-induced behaviour mediated by the central dopaminergic systems.
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Affiliation(s)
- Y Arai
- Department of Pharmacology, School of Medicine, Showa University, Tokyo, Japan
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15
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Furtado JC, Mazurek MF. MPTP-induced neurotoxicity and the quest for a preventative therapy for Parkinson's disease. Neurol Sci 1991; 18:77-82. [PMID: 2036621 DOI: 10.1017/s0317167100031346] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Less than 10 years have passed since the discovery that 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is capable of producing parkinsonism in both humans and non-human primates. In that time, there has been considerable interest in the possibility that the pathogenesis of idiopathic Parkinson's disease (PD) might involve a process analogous to that of MPTP toxicity. One hypothesis holds that PD might arise, at least in part, from exposure to an MPTP-like environmental toxin. Rapid progress has been made towards elucidating the precise mechanism by which MPTP exerts toxicity, and clarifying the relationship of MPTP toxicity to idiopathic PD. The goal of these efforts is to develop a therapy that inhibits the underlying disease process in PD.
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Affiliation(s)
- J C Furtado
- Department of Biomedical Sciences, McMaster University Medical Centre, Hamilton, Ontario, Canada
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16
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Luthman J, Sundström E. No apparent difference in the effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on the sympathetic system in NMRI and C57 BL/6 mice. Toxicol Lett 1990; 54:83-92. [PMID: 2123046 DOI: 10.1016/0378-4274(90)90059-u] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The parkinsonism-inducing neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been shown to possess marked species as well as strain differences in toxicity on central catecholaminergic systems. In the present study the effects on the peripheral sympathetic nervous system following treatment with MPTP, as well as its metabolite 1-methyl-4-phenylpyridine (MPP+) and the catecholamine neurotoxin 6-hydroxydopamine (6-OHDA) were studied in mice of the NMRI and C57 BL/6 strains, two strains that possess marked difference in MPTP toxicity on central catecholaminergic neurons. No strain differences in the depletions of noradrenaline (NA) in iris and heart auricula and of NA and dopamine (DA) in superior cervical ganglion or in the reduction of the in vitro [3H]NA uptake in iris or heart auricula were found following MPTP treatment (2 X 40 mg/kg s.c., 2 and 7 days). Treatment with the NA uptake blocker desipramine (DMI) did not affect the MPTP-induced NA depletion in either strain. Following treatment with MPP+ (30 mg/kg i.v., 7 days) no differences in the two strains were seen on the reduction of NA levels in iris and heart auricula or decrease in [3H]NA uptake. In addition, no differences were found on NA levels in iris and heart auricula after 6-OHDA treatment (15 mg/kg i.v., 7 days). The data indicate that in the NMRI and C57 BL/6 mice peripheral NA neurons do not possess any notable strain difference in the vulnerability to MPTP or in the mechanism of action of MPTP.
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Affiliation(s)
- J Luthman
- Department of Histology and Neurobiology, Karolinska Institute, Stockholm, Sweden
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